Folding knives typically include a handle and one or more blades pivotally attached to the handle, the blades having a compact closed position and an extended open position. A user opens the blade by grasping the blade or pushing a knob protruding from the blade in order to rotate the black into the open position. A folding knife may have a locking mechanism configured to lock the blade into one or both of the closed or open positions. A number of locking mechanisms are known. One such locking mechanism is the liner lock which has a spring portion that the user slides with his thumb to lodge the spring portion under the tang of the blade keeping the blade in the open position. To close the blade, a user slides the spring portion from under the tang of the blade and then rotates the blade to the closed position. However, over time the spring safety can become weak or the user may inadvertently slide the spring safety from under the tang of the blade allowing the blade to close during use leading to a cut to the user or poor functioning of the knife as a cutting tool.
As an added safety, some knives have a rotational safety that when rotated in the ‘safe’ position further secures the spring portion of the liner under the tang of the blade by sliding a safety engagement end under the spring portion. Until the rotational safety is rotated to the ‘safe off’ position, the user cannot inadvertently slide the spring safety free of the tang of the blade.
It is well-known that folding knives will loosen in the blade pivot area over time. A worn knife safety may become less functional and inadvertently dislodge the safety that is intended to maintain the position of the blade whether in the open or the closed position.
There is a need for a safety feature that is adjustable as the knife becomes worn and the safety features become less effective thereby compromising the safety and usefulness of the knife.